Chapter 60 - Tickborne Encephalitis Vaccines

Abstract

ATickborne encephalitis virus (TBEV) is a member of the genus Flavivirus, family Flaviviridae. TBEV is one of the major human pathogenic flaviviruses, with the disease being caused by three subtypes termed European or Central European (TBEV-Eu), Far Eastern or Russian Spring Summer encephalitis (TBEV-Fe), and Siberian (TBEV-Sib).1 TBEV is the prototype member of the mammalian tickborne virus complex (previously known as the tickborne encephalitis [TBE] serocomplex), a group of genetically and serologically related viruses including Omsk hemorrhagic fever virus (OHFV), louping ill virus, Langat virus (LGTV), Kyasanur Forest disease virus (KFDV), Powassan virus (POWV), and Alkhumra virus (AHFV). OHFV, KFDV, and Alkhumra virus are also associated with hemorrhagic fever, while Powassan virus and louping ill virus mostly cause subclinical disease with occasional cases of encephalitis. LGTV does not typically infect humans and appears to be naturally attenuated. There are six licensed inactivated vaccines against members of the TBEV serocomplex. Two prepared against TBEV-Eu using strains Neudorfl and K23, three prepared against TBEV-Fe using strains Sofjin, 205 and Senzhang, and one vaccine prepared against KFDV. There are no vaccines for OHFV, AHFV and POWV. Where introduced, vaccination has led to a significant decline in disease incidence.